Comparative study of three models of extra-articular distal humerus fracture osteosynthesis using the finite element method on an osteoporotic computational model

doi:10.1016/S0020-1383(13)70200-6

Injury

Volume 44, Supplement 3, September 2013, Pages S56-S61

https://doi.org/10.1016/S0020-1383(13)70200-6 Get rights and content

Abstract

Introduction

The biomechanical properties of extra-articular fractures of the distal humerus have not been researched sufficiently. The aim of the study was to examine three different models of osteosynthesis for extra-articular distal humerus fractures. Osteosynthesis with two parallel or perpendicular plates is a common method of osteosynthesis for those fractures. We wanted to examine the biomechanical performance of a newly designed Y plate, and compare it to the previously used osteosynthesis methods.

Materials and methods

On an osteoporotic computational model of the distal humerus, a 10 mm gap was made, 25 mm above the olecranon fossa, and osteosynthesis was performed with the newly designed Y-shaped plate and with 3.5 reconstruction plates in parallel and perpendicular configuration. The numerical simulations in axial compression, bending and varus loading were conducted using the finite element method.

Results

On all models the largest displacements in the area of the fracture gap appear around the lower anterior edge. The parallel plate construct had the highest stiffness among the three plating techniques in axial compression. In bending and varus loading the construct with the newly designed plate had the highest stiffness, but in axial compression demonstrated the lowest. The parallel plate configurations had higher stiffness than the perpendicular ones in all three loading directions and the difference is most pronounced in axial compression.

Conclusion

The displacements that appeared in all three plating systems are minimal and within the limits that meet the requirements of sufficient biomechanical stability in the usual time for the healing of fractures in that region. The newly designed Y-shaped plate for extra-articular fractures of the distal humerus is a possible alternative to the usual method of osteosynthesis with two plates in the case of an extra-articular fracture of the distal humerus. Further biomechanical studies are needed for a decisive conclusion.

Introduction

Although there is still some controversy regarding the treatment of extra-articular distal humerus fractures, many surgeons recommend surgery with plates and screws,1, 2, 3, 4, 5, 6, 7 while others give precedence to functional bracing, even in the case of a radial nerve lesion.8, 9 Robinson et al.¹ reported a better healing response in operated patients with an extra-articular metaphyseal fracture of the distal humerus compared to patients treated non-operatively. Jawa et al.¹⁰ found a more significant loss of elbow and shoulder function in non-operated vs. operated patients, and concluded that operative treatment provides a quicker and more complete recovery, warning, however, that it also increases the risk of complications in the form of iatrogenic injuries of the radial nerve and wound infection.

The main objective in the management of these fractures is to re-establish alignment and obtain stable fixation in order to facilitate as soon as possible early range of motion, which is necessary for a good functional outcome.2, 3

Distal humeral fractures have a relatively small incidence, but a large number of subtypes.⁹ No prospective randomized studies have been published on their outcomes, and the majority of the studies carried out were retrospective and involved a small number of patients.10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23

Hence it is not possible to draw conclusions from them on the ideal configuration of the implant for stabilization of distal humerus fractures.

There have been no studies dealing with fractures on the transition of the distal diaphysis into the distal humerus. In this region, no studies have been conducted using the finite element method.

The aim of this study was to preconfigure the Y reconstructive plate intended primarily for the treatment of intra-articular fractures of the distal humerus, and to convert it for extra-articular fractures of the distal humerus and distal humeral diaphysis, as well as to examine its biomechanical performance comparing it to the existing osteosynthesis methods with two reconstruction plates in perpendicular and parallel position using the finite element method. Our hypothesis was that the osteosynthesis with a novel Y plate would show at least the same stability of distal humerus fractures as well as the double plating systems with reconstruction plates in parallel and perpendicular configuration.

The finite element method is a highly valuable test method comparable in value to experimental biomechanical studies.²⁴

Section snippets

Materials and methods

Computational simulations using the finite element method were performed with the models of the test and control groups under axial, lateral and bending load.

The test model was a construction with the newly designed titanium plate (Figure 1a) placed on the bone with 12 titanium screws, and the control models were parallel (Figure 1b) and perpendicular steel reconstruction plates (Figure 1c), with the arrangement of screws as shown in the figures. In both control models, two 3.5 reconstruction

Results

In all samples, maximum displacements appear on the distal articulation part more pronouncedly on the radial column, and are the largest in bending. Figure 3 shows the control group model with a perpendicular configuration of the reconstruction plates under lateral load in which the displacements are the largest.

Maximum displacements on the models of the test and control groups for all three loading directions are shown in Figure 4, and the stiffness under the same loading conditions in Figure 5

Discussion

All of the previous biomechanical studies dealing with distal humeral fractures established the articular or immediate supracondylar level as the site of instability, which is imitated by the gap in the biomechanical model.11, 13, 14, 15, 16, 17, 18 No study to date has addressed the issue of biomechanical stability on the transition of the distal humeral diaphysis into the distal segment of the humerus.

The objective of the study was to examine the biomechanical properties of the newly

Conclusion

Under physiological loads, the radial column withstands greater loads, and displacements in the radial articulation surface are more pronounced. For that purpose, in extra-articular fractures of the distal humerus the implant should provide greater stability in the radial column area. In all three models (both the control and test models), the displacements occurring after all three loads are minimal and within the range that fulfills the requirements of sufficient biomechanical stability in

Conflict of interest

All authors have no financial and personal relationships with other people or organisations that could inappropriately influence of the work.

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Comparative study of a Y- anatomical and innovative locking plate versus double plate for supracondylar humeral fracture
2023, Orthopaedics and Traumatology: Surgery and Research
There is no “gold standard” for the type of plate to be used for distal extra-articular humeral fractures; the most used is plating of each column. The objective was to evaluate the short-term clinical and radiological results of a Y- anatomical and innovative locking plate (YALP).
The hypothesis is: this anatomical and innovative locking plate will produce satisfactory and reliable results on extra-articular distal humerus fracture superior to double plate fixation.
In a retrospective observational multicenter study, all patients with a distal humerus fracture type 13 A2.2 according to AO classification fixed with a new Y-plate (YALP) were compared to the results of double plate fixation for the same type of fracture. With a follow-up of more than 12 months, the objective and subjective clinical elbow criteria as well as the overall function of the upper limb and radiological assessment were collected.
With an average follow up of 24 ± 11 months, 26 patients met the inclusion criteria and received a YALP and 24 patients received double plate. All patients whose fracture had healed except one were pain-free (mean VAS 0.3 ± 0.6). All patients had good subjective results (mean SEV 96% ± 4). Elbow function was excellent (mean total MEPS 96 ± 4) with normal triceps strength (23/24 patients had a triceps strength graded 5/5 and one patient 4/5) and range of motion (flexion 139 ± 8, extension −7 ± 8 and pronosupination greater than 155 degrees). The operating time was shorter in the YALP group (84 ± 23 minutes versus 97 ± 28 minutes, p = 0.03). The double plate group had more complications; the overall complication rate was significantly higher (p = 0.02) in the double 90-degree plate group (12/24, 50%) with four nonunions, four symptomatic ulnar nerves, three hardware removals for pain and one radial nerve injury versus 5/26 complications (19%, p = 0.02) in the Y-plate group: one iliac graft for nonunion, 1 plate removal due to functional discomfort, 1 twisted YALP, 1 broke interfragmentary screw and one symptomatic ulnar nerve. DASH, SEV, MEPS scores and flexion-extension range were better in the YALP group.
YALP produces satisfactory results in supracondylar fractures of the distal humerus. The results of YALP appear to be better than the results with two 90° plates for the same fracture type with a shorter operative time and easier management of fractures with proximal diaphyseal extension.
III; case control study.
Comparative study of a Y-anatomical and innovative locking plate versus double plate for supracondylar humeral fracture
2023, Revue de Chirurgie Orthopedique et Traumatologique
Aucun « gold standard » n’existe concernant le type de plaque à utiliser pour les fractures distales extra-articulaires de l’humérus ; la technique la plus utilisée est une plaque sur chaque colonne. L’objectif était d’évaluer les résultats cliniques et radiologiques à court terme d’une plaque de verrouillage anatomique et innovante en Y (YALP).
Cette plaque de verrouillage anatomique et innovante (YALP) donne des résultats satisfaisants et fiables sur les fractures extra-articulaires de l’humérus distal, supérieurs à la fixation par double plaque.
Dans une étude rétrospective observationnelle multicentrique, tous les patients présentant une fracture de l’humérus distal de type 13 A2.2 selon la classification AO fixée avec une nouvelle plaque en Y (YALP) ont été comparés aux résultats de 2 plaques d’humérus distal à 90 degrés pour le même type de fracture. Avec un suivi de plus de 12 mois, les critères cliniques objectifs et subjectifs du coude ainsi que la fonction globale du membre supérieur et l’évaluation radiologique ont été recueillis.
Avec un suivi moyen de 24 ± 11 mois, 26 patients répondaient aux critères d’inclusion et ont eu une YALP et 24 patients ont eu 2 plaques à 90. Tous les patients dont la fracture a consolidé (hormis un patient) étaient indolores (EVA moyenne de 0,3 ± 0,6). Tous les patients avaient de bons résultats subjectifs (SEV moyen 96 ± 4 %). La fonction du coude était excellente (MEPS total moyen 96 ± 4) avec une force du triceps normale (23/24 patients avaient une force du triceps notée 5/5 et un patient à 4/5) et une mobilité satisfaisante (flexion 139 ± 8, extension -7 ± 8 et prono-supination supérieure à 155 degrés). La durée de l’opération était plus courte dans le groupe YALP (84±23 minutes contre 97±28 minutes, p = 0,03). Le taux global de complications était significativement plus élevé (p = 0,02) dans le groupe à 2 plaques à 90 degrés (12/24, 50 %) avec quatre pseudarthroses, 4 nerfs ulnaires symptomatiques, 3 retraits de matériel pour cause de douleur et une lésion du nerf radial contre 5/26 complications (19 %, p = 0,02) dans le groupe plaque en Y : une greffe iliaque pour pseudarthrose, 1 retrait de plaque pour cause de gêne fonctionnelle, 1 YALP tordue, 1 vis interfragmentaire cassée et un nerf ulnaire symptomatique. Les scores DASH, SEV, MEPS et la mobilité en flexion-extension étaient meilleurs dans le groupe YALP.
Les plaques YALP donne des résultats satisfaisants dans les fractures supra condyliennes de l’humérus distal. Les résultats de YALP semblent être meilleurs que ceux obtenus avec deux plaques à 90° pour le même type de fracture avec un temps opératoire plus court et une gestion plus facile des fractures avec extension diaphysaire proximale.
III ; étude cas-témoin.
Length of Plates and Number of Screws for the Fixation of Distal Humerus Fractures: A Finite Element Biomechanical Study
2022, Journal of Hand Surgery
Citation Excerpt :
It is up to the surgeon’s discretion to choose the minimum screws required or the optimum number of screws, by considering the fracture pattern, bone quality, bone contact, and compression across the fracture. The loads applied in our study were within the physiologic limits of loads used during activities of daily living.25–27 We avoided applying loads that would cause permanent plastic deformations in the implants.
We performed a biomechanical analysis using the finite element method to assess the effects of plate length and the number of screws on construct stiffness, stress distribution, and fracture displacement in the fixation of type A2 distal humerus fractures.
A 3-dimensional humerus model was constructed using computed tomography of a healthy man. After creating a 2-mm extra-articular fracture gap, orthogonal double-plate fixation was performed with an incremental increase in plate length and the number of screws, creating 17 fixation models. Four screws were placed in each plate’s distal segment, and the number of screws was increased incrementally in the segment proximal to the fracture, starting from 2 in the medial (M) and 2 in the lateral (L) plate (M2∗L2).
The fifth screw proximal to the fracture in the lateral plate (L5) played an essential role in increasing stiffness under bending, axial, and torsional forces surpassing the intact bone, which may have been due to the bypassing of the stress riser area. Minimum construct stiffness was created when 5 (M3∗L2) screws were inserted into the proximal segment. For bending forces, the M4∗L2 construct was stronger than M3∗L3 (total 6 proximal screws), and M5∗L3 was stronger than M4∗L4 (total 8 proximal screws), showing higher stiffness when the plates ended at different levels. The M4∗L2 construct (6 screws) had stiffness comparable with M4∗L3, M4∗L4, and M5∗L4 during bending, showing comparable stiffness with the least instrumentation density.
Our findings suggested M3∗L5 as the optimum and M3∗L2 as the minimum construct to resist all bending, axial and torsional forces.
Applying the results may improve surgical techniques, decrease the rate of complications, including fixation failure and nerve injury, and optimize the time of surgery. Moreover, hardware removal is less cumbersome with fewer screws.
How can medial support for proximal humeral fractures be achieved when positioning of regular calcar screws is challenging? Slotting and off-axis fixation strategies
2022, Journal of Shoulder and Elbow Surgery
Citation Excerpt :
The elastic modulus and Poisson ratio of the plate and screw were set to 105 GPa and 0.3, respectively. The material properties of the synthetic bone were set according to the method of Sabalic et al,26 with an elastic modulus of 8200 MPa in the axial position, 16,500 MPa in 20° abduction, 21,000 MPa in 20° adduction, and a Poisson ratio of 0.4. The boundary conditions were established in accordance with the compressive testing (Fig. 3, c).
Achieving medial support for proximal humeral fractures (PHFs) by regular calcar screw positioning is challenging when the humeral head is small or locking plates are placed distally, as there are unable inserted calcar screws into the humeral head. We aimed to investigate the suitability of the 2 strategies, slotting calcar screw (SCS) and off-axis calcar screw (OCS), to achieve medial support for PHFs.
Regular calcar screw (RCS), SCS, OCS, and noncalcar screw (NCS) were tested via mechanical experiments and finite element analysis (FEA), using synthetic bones for biomechanical comparisons. All PHFs treated in our hospital from March 2017 to March 2019 were reviewed. The patients were divided into 3 groups based on the calcar screw fixation: RCS, SCS, and OCS. The postoperative varus collapse (neck-shaft angle changed to less than 120°) and Disabilities of the Arm, Shoulder and Hand (DASH) scores were recorded.
The properties of RCS, SCS, and OCS against the torsion and varus force were superior to those of NCS, whereas the stiffness of SCS, OCS, and RCS were similar. FEA predicted lower peri-screw strains in the OCS and SCS than in the RCS, indicating a lower risk of cut-out. Patients (n = 125; 75 female, 50 male) aged 55.9 ± 13.0 years were evaluated. Compared with the RCS (5/55), varus collapse incidences were not significantly higher following SCS (0/29, P = .094) or OCS (3/41, P = .756), and neither were DASH scores (P = .867 and .736, respectively).
This study is a preliminary study demonstrating that the SCS and OCS fixation strategies could be useful alternatives when regular calcar fixation is not possible using the plate at hand.
Distal medial tibial locking plate for fixation of extraarticular distal humeral fractures; an alternative choice for fixation
2018, Acta Orthopaedica et Traumatologica Turcica
The aim of this study was to describe an alternative fixation method for distal humeral extra-articular fractures through posterior approach using distal tibia anatomic locking plate; and to evaluate the patient's functional outcome and union condition.
Eighteen patients (11 men and 7 women; average age of 37.0 ± 17.3 years (range: 18–73 years)) with a distal humeral extra-articular fracture who were treated with distal tibial medial locking plate were included into the study. The mean follow up time was 36.2 ± 16.7 (12–57) months. Functional results were evaluated with perception of pain, range of joint motion, grasp and pinch strengths.
Union was achieved in 17 of 18 patients. Only one patient had non-union due to infection and underwent debridement. The mean time for union was 7.8 ± 5.9 months (2–20). Patient perception of pain was X = 1.88 ± 2.50 and X = 4.55 ± 2.68, respectively, at rest and activity. The active ranges of joint motion were adequate for functional use. General functional state of affected extremity (DASH-T) was perfect (X = 27.14 ± 25.66), the performance of elbow joint was good (X = 84.44 ± 11.57). There were no differences in the comparison of grasp and pinch grip of patients with uninvolved extremity (p > 0.05).
In distal humeral extra-articular fractures, use of distal medial tibia plate has advantages such as providing high rates for union, low rates for complication, and early return to work with early rehabilitation, therefore it may be considered a fixation choice that can be used for distal humeral extra-articular fractures.
Level IV, therapeutic study.
Best care paradigm to optimize functionality after extra-articular distal humeral fractures in the young patient
2018, Journal of Clinical Orthopaedics and Trauma
For younger patients with extra-articular distal humerus fractures closed management is plagued with high rates of malunion, suboptimal functional outcomes, extended immobilization with loss of early motion, a delay in return to work, and a general period of lost productivity. Surgical management offers an appealing alternative. Maintaining respect for the triceps musculature and minimizing iatrogenic injury to the radial nerve are primary concerns with operative treatment. Accordingly, use of a triceps-sparing approach and single column plating may be the optimal treatment paradigm in the young patient presenting with an extra-articular distal humerus fracture.

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Comparative study of three models of extra-articular distal humerus fracture osteosynthesis using the finite element method on an osteoporotic computational model

Abstract

Introduction

Materials and methods

Results

Conclusion

Introduction

Section snippets

Materials and methods

Results

Discussion

Conclusion

Conflict of interest

Clin Biomech (Bristol, Avon)

Clin Biomech (Bristol, Avon)

J Shoulder Elbow Sur

J Shoulder Elbow Surg

Injury

Injury

Injury

Clinical Biomechanics

J Shoulder Elbow Surg

J Shoulder Elbow Surg

Adult distal humeral metaphyseal fractures: epidemiology and results of treatment

J Orthop Trauma

An alternative method of osteosynthesis for distal humeral shaft fractures

J Orthop Trauma

Elements for successful functional result after surgical treatment of intra-articular distal humeral fractures

Acta Clin Croat

Dual plating for fractures of the distal third of the humeral shaft

J Orthop Trauma

Fractures of the distal humerus